Printed circuit boards (PCBs) typically comprise an insulating substrate (e.g., glass fiber reinforced epoxy or polyimide film) which supports a thin conducting layer (usually copper) in a pattern designed for a specific application. The patterned conducting layer (also referred to as a printed circuit), is the means for carrying electrical voltages and currents between various electrical components, such as resistors, capacitors, integrated circuits and other electronic devices. Typically, the circuit pattern (i.e. wiring configuration) is produced by a photolithography process that tends to be rather complex and costly. It would thus be advantageous if the image data could more simply and/or more economically transferred onto a circuit board using an alternative, non-lithographic process.
During the process of laser patterning of circuit boards with activatable fillers, debris is generated from ablation during the patterning process. Some of the debris is deposited on the surface of the dielectric or insulating substrate. During the plating step, the activated debris on the surface will be metallized. The varied size of the conductive features can contribute to under-plating or over-plated for a given plating time. Over-plating can occur resulting in traces or paths that are not clean.
A need exists for eliminating over-plating in the lines and spaces. Over-plating can allow charge to flow along a different path than the one intended causing a short.